Compare carpet stain removers for their effectiveness?

Compare carpet stain removers for their effectiveness?

 
Introduction:
General purpose detergents may not be able to remove certain types of stains on clothing, carpet or any other fabric. Some stains produce a mechanical bind with the fiber of the fabric. Some other stains create a molecular bound. In either way, a more effective stain remover is needed to remove them.

Almost all manufacturers of stain removers claim that their product is the best and is the most effective; however, that might not be the case for every type of stain.